TonB-dependent receptors
Encyclopedia
TonB-dependent receptors is a family
of beta-barrel proteins from the outer membrane of Gram-negative bacteria. The TonB complex senses signals from outside the bacterial cell and transmits them via two membranes into the cytoplasm, leading to transcriptional activation
of target gene
s.
In Escherichia coli
the TonB protein interacts with outer membrane receptor proteins that carry out high-affinity binding and energy-dependent uptake of specific substrates into the periplasmic space. These substrates are either poorly permeable through the porin channels or are encountered at very low concentrations. In the absence of TonB, these receptors bind their substrates but do not carry out active transport. TonB-dependent regulatory systems consist of six protein protein components .
The proteins that are currently known or presumed to interact with TonB include BtuB, CirA, FatA, FcuT, FecA, FhuA, FhuE, FepA, FptA, HemR, IrgA, IutA, PfeA, PupA and Tbp1. The TonB protein also interacts with some colicins. Most of these proteins contain a short conserved region at their N-terminus.
Protein family
A protein family is a group of evolutionarily-related proteins, and is often nearly synonymous with gene family. The term protein family should not be confused with family as it is used in taxonomy....
of beta-barrel proteins from the outer membrane of Gram-negative bacteria. The TonB complex senses signals from outside the bacterial cell and transmits them via two membranes into the cytoplasm, leading to transcriptional activation
Transcription (genetics)
Transcription is the process of creating a complementary RNA copy of a sequence of DNA. Both RNA and DNA are nucleic acids, which use base pairs of nucleotides as a complementary language that can be converted back and forth from DNA to RNA by the action of the correct enzymes...
of target gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
s.
In Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
the TonB protein interacts with outer membrane receptor proteins that carry out high-affinity binding and energy-dependent uptake of specific substrates into the periplasmic space. These substrates are either poorly permeable through the porin channels or are encountered at very low concentrations. In the absence of TonB, these receptors bind their substrates but do not carry out active transport. TonB-dependent regulatory systems consist of six protein protein components .
The proteins that are currently known or presumed to interact with TonB include BtuB, CirA, FatA, FcuT, FecA, FhuA, FhuE, FepA, FptA, HemR, IrgA, IutA, PfeA, PupA and Tbp1. The TonB protein also interacts with some colicins. Most of these proteins contain a short conserved region at their N-terminus.